Hydraulic caster lift



March 9, 1954 G, Ewl3 2,671,242

HYDRAULIC CASTER LIFT Filed April 6, 1951 2 Sheets-Sheet l E z2 l ,2% 4

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March 9, 1954 G. L. LEWIS HYDRAULIC CASTER LIFT 2 Sheets-Sheet 2 FiledApril 6, 1951 INVENTOR,

l I l Patented Mar. 9, 19574 UNITED STATES .tr-teur orifice 2.671,24?.irizimvic oAsrEi't LIFT Gilbert L; Lewis, Kansas ity, Mo. ApplicationApril e, 1951, serial No. Tais-,esi

(c1. 16e-e3) 1 Clain.

invention relates to new and useful prvenents in hydra xcally operatedcasters particularly adapted lfor use 'on heavy furniture lappliances. v

T-h'e principal object of the present invention is the bro'vision of a'casteihaving a hydraulically driven 'piston `so that bye-poration of amaster hydraulic cylinder the rollers are projected from a 'ce'ss inthehydraulic ycylinder and the Weight of the appliance to tva-:eh thecasters ere attached is taken by Athe casters to permit 'easy rolling'of the appliance about the neer.

A further 'object of my invention is to provide a relatively largerestingsurface on which the appliance ris `supported when the caster isre- 1 tracted into the recess in the hydraulic cylinder, therebypreventing damage tothe floor surface.

Other objects vare ease and kconvenience of per'ation, simplicity /o'finstallation 'and economy @construction With 4these objects in view,others which will appear 'during the'c'ours'e oi the specification,reerence will be had to the drawings, wherein:

Fig. 1 is a schematic View showing the hyfaulicfs'ystern used innlyvinvention.

Fig. 2 is a longitudinal sectional view of a caster with some parts left4in elevation and eine staying a preferred term of my intention, Snow;ing 'the dvic with th hydraulic pressure e leafsed.

Fig. 3 is a longitudinal sectional view similar to Fig. 2 and 'showingthe device with the caster lowered 'into 'operable position by hydraulicpres'- sure.

Trie. i S en inverted pian 'view of 'the device supwnmrigs-.zand3- ,5 is"a retluc'z'ed 'side eievatio'n'of a hiodied (forni of 'my invention.

Fig. 6 is an enlarged longitudinal sectional View of 't'l'i device shownin Fig. 5, with parts left in elevation, and 'showing the device withthe hydraulicpressurereleased,

Fig. '7 is "a View sirni'lar to-Fig. -6`and showing the device with theresting surface 'lowered into oper'- abl'e position by hydraulicpressure.

Fig. B is fa npartial sect-ional view taken on line VTI-VIH'O Fig. 6.

Fig. 9 is a partial sectional View taken on line IX--IX of Fig. 7.

Fig. 10 is an inverted plan view of the device in the modied form.

Like numerals refer to similar parts throughout the several views andnumeral l0 refers to a caster in the preferred form having a housing I2.Said housing has a flange I4 formed at its lower edge to present aizbhftal s'urfacen its l'w and upper steeg; sain housing als@ leas gasnoutder Iii intermediate its ends which extends' hr-ie Zontallyinwardly rna point directly abve 'the inner edge of flange i4, for apurpose to de scribed later in 'the fele'cication. "The upper end oflsaid. housing is oled heifiz'ohftally l'and is irivided with a threadedhole fa which a nigh pressure tube 2B is `securely attached. Hydraulicfluid is admitted th'ieu'gh itu-be )Eli inte harrib'o'r 22 formed by theinternal walls of housing lf2 and c'up 24 which forms the llower" side fsaid cham ser. @up 'conferentie to the inner walls of housing l2 andwhen hydraulic pressure is bre-isnt aga-nist will 'tr-event ieaizegfe'et trie flu-id between the 'cup iand tire inner housing walls.

Said cup k24 is securely attached to upper Side 0i piston 2%. Piston 26ycon-foifns t'o the 'shape or vchamber 22 and @neatly inserted therein.The lower portion or said piston is 'hollow and formed to receive rollerbal-l 7238. Said r ler hall is rotatable held Ain ''opera-ble po n bymeans -of inwardly siv'edged lower "edgeE piston .a 2e. een bearing-3 0is carried 'with-"m tire ifi-@Haw portion 0'; piston 'is and is disposedse that teneij'oall 2li rotates 'thereon when the ball 28' has beenlowered into iieratingpo'sit'ion by nean's dra'uli'c pressure :exerted'on cup 'f4 and piston 276, as best shown in Fig.'3.

Intermediate its ends nreviedw'itjh e ras-iai piston 2s is flange 32which extends noritontaily outwardly fmmjsaid pieten anzi is disposedtee heath shoulder es. A plurality et fequaistanftiy spaced bolts 34 are'secured to shoulder 'F6 and extend downwardly therefrom `to a pointaddacent Vthe floor surface. Said bolts Ail?! slid "ly extend. throughholes 3s frange 32. springs 38 are suitably placed on bolts 35 and'disposed betweenthe heads of bolts Sii and shoulder -lt Intermediate'the ends et 'toits e4 are fsnduitirs el! whose purpose will bedescribed later.

The caster lis attached to 'ftnitiire or applianc''s '1512 by ine'ahsef`a plurality f'o'f sc'r'etlfs-'M which extend 'through frange N fand'into 'the niture L'er appliance. A *pad fAS of felt or 'other suitablematerial is attached 4to the under `side of iiange I4. Said pad iscutaway around bolts 44 so that the pad extends below the heads of saidbolts.

When the caster is its normal position piston 26 is held at the upperend of its stroke by means of springs 38. The upward stroke of saidpiston is limited by the contact of flange 32 with shoulder I6 as shownin Fig. 2. When the caster is in its normal position and roller ball isretracted above the iioor surface and the weight of the furniture orappliance is supported on Dad 46.

When hydraulic pressure is applied piston 25 is lowered and the weightof the appliance is transferred from the said pads to the roller ball28. The downward movement of the piston is limited by the contact offlange 32 with shoulders 48. Thus when the piston has been completelylowered the furniture or appliance may be easily moved about on roller28. When the appliance or furniture is in the desired place thehydraulic pressure may be released and the piston 26 will be urged againto the upper end of its stroke by springs 38 and the furniture orappliance will again be supported on the protective pads 46.

'I'he hydraulic system used with this device is schematically shown inFig. 1 and consists of a pump 48 the intake of which is connected to areservoir tank 58 by means of tube 52. The delivery side of pump 48 isconnected through common tube 54 to tubes 28. Intermediate the pump andtubes 28 is a check valve 56 in tube 54 to prevent the flow of hydraulicuid back to the pump. A return tube 58 is connected at one end to commontube 54 at a point between the check valve 56 and tubes 28 and at theother end to reservoir tank 50. A valve 68 is in' return tube 58 at apoint between the reservoir tank and the common tube 54. Said valve 68being for the purpose of relieving the hydraulic pressure on pistons 26when it is desired to allow the casters to assume their normalpositions.

A modified form of my invention is shown in Figures 5, 6, 7, 8, 9, and10, and embodies the same principles as are described in the preferredform.

In the modified form 62 indicates a housing comprising a cylinder havinga, concentric annular groove 64 formed in its lower side adjacent itsperiphery and extending upwardly to a point adjacent the upper end ofthe housing forming an annular hydraulic cylinder. Said cylinder alsohas a recess 66 formed centrally in its lower side. Ball bearing 38 isattached to the upper wall of recess 66. Said recess 66 is of suchdiameter as to leave depending skirt 68 between said recess and annulargroove 64 and extends deep enough to allow roller ball 28 to rotatefreely therein.

Roller ball 28 rotates on ball bearing 38 and extends below the loweredge of depending skirt 58 and is held in an easily rotatable positionby means of an annular retainer ring 18 which is attached to the loweredge of depending skirt l68 by means of a plurality of bolts 12. Saidretainer ring is beveled inwardly at its inner periphery to retainroller ball 28 in operable position when no weight of the appliance ison said ball. Said retainer ring extends outwardly to a point beyond theouter edge of said depending skirt 68.

Annular piston 14 is slidably received in annular groove 64. The lowerinner periphery of said circular piston is indented, said indentation 82extending to a point adjacent the upper surface of said circular piston.Annular cup 16 is 4 attached to the upper side of annular piston 14 andslides with said piston and is conformable to annular groove 64.Hydraulic uid is admitted to said annular groove through hole 18 inupper side of housing 62.

When hydraulic fluid pressure is urged against circular cup 16, circularpiston 14 is moved downwardly against spring 80. Said spring 88 issuitably placed adjacent the outer periphery of depending skirt 68 anddisposed between retainer ring 18 and the upper end of indentation 82.When hydraulic uid pressure is released from the circular cup 16, spring88 urges circular piston upwardly.

A pad 84 of felt or other suitable material is attached to the lowersurface of piston 14 to protectthe oor surface on which the device isresting.

In the modified form the caster is attached to the furniture orappliance 42 by means of a plurality of bolts 85 which extend throughthe lower portion of the appliance and are attached to the upper portionof the housing 62.

Thus it can be readily seen that when the caster in the modified form isin its normal position the roller ball 28 is resting on the floorsurface as shown in Fig. 6 and the appliance or furniture can be easilymoved about. When hydraulic fluid pressure is exerted on circular cup16, said cup and piston T4 are moved downwardly and the weight of thefurniture or appliance is supported on the said piston and the rollerball is moved relatively upwardly above the oor surface.

Having fully described my invention what I claim is:

A hydraulic caster lift comprising a housing forming a hydrauliccylinder open at its lower end, said housing presenting a horizontalshoulder intermediate its ends extending outwardly at the lower end ofsaid hydraulic cylinder, a piston carried operably in said cylinder, aroller carried operably in said piston and extending below said piston,a cup conformable to inner walls of said hydraulic cylinder attached tothe upper end of said piston, a ange formed on the outer periphery ofsaid piston extending horizontally therefrom and disposed below saidshoulder, a plurality of depending bolts attached to said shoulder andextending slidably through said piston flange, resilient means carriedby said bolts and disposed between heads of said bolts and said pistonflange whereby to urge said piston to the upper end of its stroke, andmeans whereby hydraulic fluid is introduced into said cylinder at apoint above said cup for moving said piston from a position entirelywithin said housing to a position extending below said hous- 111g.

GILBERT L. LEWIS.

References Cited in the ille of this patent UNITED STATES PATENTS NumberName Date 1,016,324 Dunn Feb. 6, 1912 2,045,524 Fehrmann June 23, 19362,226,970 Engel Dec. 31, 1948

